title: Self-assembled 3D ZnO porous structures with exposed reactive {0001} facets and their enhanced gas sensitivity.
abstract: Complex three-dimensional structures comprised of porous ZnO plates were synthesized in a controlled fashion by hydrothermal methods. Through subtle changes to reaction conditions, the ZnO structures could be self-assembled from 20 nm thick nanosheets into grass-like and flower-like structures which led to the exposure of high proportions of ZnO {0001} crystal facets for both these materials. The measured surface area of the flower-like and the grass, or platelet-like ZnO samples were 72.8 and 52.4 m2∙g-1, respectively. Gas sensing results demonstrated that the porous, flower-like ZnO structures exhibited enhanced sensing performance towards NO2 gas compared with either grass-like ZnO or commercially sourced ZnO nanoparticle samples. The porous, flower-like ZnO structures provided a high surface area which enhanced the ZnO gas sensor response. X-ray photoelectron spectroscopy characterization revealed that flower-like ZnO samples possessed a higher percentage of oxygen vacancies than the other ZnO sample-types, which also contributed to their excellent gas sensing performance.
authors.affiliation: School of Chemistry, Physics & Mechanical Engineering, QUT, Brisbane, QLD 4000, Australia. cj4566@gmail.com
authors.forename: Jin
authors.initials: J
authors.lastname: Chang
authors.forename: Muhammad Z
authors.initials: MZ
authors.lastname: Ahmad
authors.forename: Wojtek
authors.initials: W
authors.lastname: Wlodarski
authors.forename: Eric R
authors.initials: ER
authors.lastname: Waclawik
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005740:Gases / Q000032:analysis*; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D008968:Molecular Conformation; D036103:Nanotechnology / Q000295:instrumentation*; D009569:Nitric Oxide / Q000032:analysis*; D010316:Particle Size; D014159:Transducers; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D005740:Gases; D009569:Nitric Oxide; D015034:Zinc Oxide